"An apple a day keeps the doctor away"is one of the most common sayings in the English languages．This is because apples were one of the first foods that medical professionals recognized as healthy-their benefits became obvious when，quite simply，doctors found that people who ate apples were sick less often than those who did not．Today we have a more specific understanding of why apples are so beneficial to overall health．
Apples can help keep your levels of bad cholesterol （胆固醇） down．The pectin （果胶） in apples helps you to maintain cardiovascular health and reduce LDL cholesterol（which is the"bad"kind）．Apples themselves do not add cholesterol to your diet and are full of water and fiber to help prevent the cholesterol in other foods you might digest．According to Health Diaries，people who eat two apples per day may lower their cholesterol by as much as 16percent．
Apples are naturally low in calories and high in water content．Eating an apple can satisfy your hunger and keep you from reaching for high-sugar，high-calories snacks．By eating apples，you will be more able to maintain a healthy weight because they fill you up，potentially stopping you from eating food that encourages a waistline increase．
Apples contain respectable levels of boron （硼），which helps build healthy bones，and can also prevent diseases like arthritis．Apples are rich in vitamin C，which is known to help build immunity．
Studies have shown that apples can decrease the risk of breast cancer，colon cancer，and liver cancer．One theory is that the apple skins are responsible for this，so be sure not to peel your apple before you eat them，as you could remove some of the health benefits．

(1) What's the main idea of the passage？ ______

A. An explanation of an English saying．

B. How to make full use of apples．

C. Apples are beneficial to our health．

D. How to keep healthy in our daily life．

(2) By eating apples we can get many benefits EXCEPT ______ ．

A. lowering the cholesterol

B. keeping a healthy weight

C. building immunity

D. preventing heart disease

(3) Which of the following can most probably replace the underlined word"respectable"？ ______

A. Admirable．

B. Considerable．

C. Reliable．

D. Valuable．

(4) Which plays an important role in reducing the risk of breast cancer？ ______

A. The pectin．	B. The apple skins．
C. The flesh of apples．	D. The fiber of apples．

(5) What's the author's attitude towards the effect of eating apples？ ______

A. Positive．

B. Negative．

C. Doubtful．

D. Uncertain．